What causes loss in coax?
There are two primary causes of signal loss with coax: 1) Resistive loss, and 2) Dielectric loss. Resistive loss arises from the resistance of the center conductor of the cable and results in dissipated heat. Radio frequency currents tend to flow along and near the surface of conductors.
What is coax cable loss?
The longer the length of a piece of coaxial cable, the more signal is lost. The higher the frequency of the signal passing through the coaxial cable, the higher the loss over a given length. Coaxial cable loss is normally specified in dB loss per 100 feet of cable.
Why is it important to know about coax cable loss?
For applications where moisture may be encountered, specialized cables should be used otherwise the performance will degrade. The loss introduced by a coax cable is obviously very important because power lost can never be regained. This can degraded the overall system performance.
What are the three main constituents of coax loss?
There are three main constituents to the coax cable loss. Resistive loss: Resistive losses within the coax cable arise from the resistance of the conductors and the current flowing in the conductors results in heat being dissipated. Dielectric loss: The dielectric loss represent another of the major losses arising in most coax cables.
How does dielectric loss affect coax cable attenuation?
Again the power as a result of dielectric loss manifests itself as heat dissipated within the dielectric. It is found that the dielectric loss is independent of the size of the RF cable, and it increases linearly with frequency. This means that resistive losses normally dominate at lower frequencies.
What causes high signal levels on coax cable?
Power radiated, or picked up by a coax cable is more of a problem in terms of interference. Signal radiated by the coax cable may result in high signal levels being present where they are not wanted.